Pump or motor.



c. R; PRATT.

PUMP 0R MOTOR.

APPLICATION FILED. DEC. 3G. I909.

Patented Dec. 14, 1915.

3 SHEETS-SHEET I".

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C. R. PRATT. PUMP 0R MOTOR.

APPLICATION FILED DEC- 30, I909- 1,l63,49. Patented Dec. 14, 1915.

3 SHEETS-SHEET 2.

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C. R. PRATT. 7 PUMP 0R MOTOR. \PPLICATION FILED DEC- 30. 19094 M mm m V 5 H m. 4 m m Q\\ n e 3 m w h 0% (ink mn 9 a; mm n Mn 9w A I ml] \w- 3 ll IILLTII m E 9% T M a .9 I Q 4 .l mt p 3 6 1 vi WITNESSES .506% A TTOR/VE V.

are sra ras PATENT onion.

CHARLES R. PRATT, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO THE UNIVERSAL SPEED CONTROL COMPANY, A CORPORATION OF NEW YORK.

PUMP OR MOTOR.

Specification of Letters Patent.

Patented Dec. 1141, 1915,

Application filed December 30, 1909. Serial No. 535,646.

To all whom it may concern:

Be it known that 1, CHARLES R. PRATT, a citizen of the United States, residing at Montclair, in the county of Essex and State of New Jersey, have invented certain Improvements in Pumps or Motors, of which the following is a specification.

This invention relates to that class of pumps or motors in which an annular series of pistons occupying cylinders therefor in a rotary barrel are connected by piston-rods of uniform length to the disk-like head of a rotary shaft disposed, or adapted to be disposed, at an angle to the axis of rotation of said cylinder barrel, whereby the rotation of said shaft will cause the pistons to pump a fluid or the forcing of a fluid through said cylinders will cause the pistons to rotate the said shaft to which they are connected. A device of this sort is shown in the patent to Holbrook F. J. Porter, No. 985.835, dated March 7 1911, and my own application Serial No. 489,976, filed April 15, 1909, has to do with the same sort of a pump or motor, the present invention consisting in certain improvements in such a pump or motor.

The objects of the invention are to hold the face or end of the cylinder barrel, through which lead theports to the piston cylinders, against its seat and which seat is in effect a valve seat; to adapt such holding and the means for doing it to various conditions of velocity and pressure of the fluid passing through the cylinders; to enable the said ports to be of equal or greater area than the cylinders; to thus'avoid throttling the flow of fluid and increasing hydraulic fric tion: to secure minimum leakage in the operation of the pump or motor or rotation of the cylinder barrel against its end seat. and to obtain other advantages and results as may be brought out in the following description. 7

Referring tothe accompanying drawings, in which like numerals o'f-reference indicate corresponding parts in each of the several figures, Figure 1 is a side elevation, partly in central longitudinal section, of a pump or motor of my improved construction especially adapted for conditions where both the pressure and velocity of the, fluid are sub stantially constant; Fig. 2 is a complete central longitudinal section of a pump or motor of my improved construction especially adapted for conditions where either the pressure or velocity of the fluid varies while the other is substantially constant, taken as to the casing on line 2-4, and as to the cylinder barrel and shaft head on line 224, both Fig. 4; Fig. 3 is a central longitudinal section through the pump or motor casing and cylinder barrel at their seat a ainst each other, taken as to the casing on line 35 and as to the barrel on line 33*85, both Fig. 4; Fig. 4 is an end view of the pump or motor, and Fig. 5 is a detail perspective view of a certain key detached;

In the pump or motor'shown in said prior Porter Patent No. 985,835, the ports of the cylinders opened through the sides of the cylinder barrel, but in still earlier patents, as for instance No. 432,359 to Robert C. Berry, July 15, 1890, the ports have opened through the end of the cylinder barrel and its end seat against the casing of'the pump or motor. In this case, the ports were restricted or of less cross-sectional area than the cylinders, for the purpose of holding the face of the cylinder barrel against its seat by the reaction of hydraulic pressure. al-- though by such restriction the flow of fluid was throttled and hydraulic friction increased. However, this was, and still is, the best construction for those conditions where both the pressure and the velocity of the fluid vary widely, but by my present invention I have devised means for using under other conditions the said end ports without the objections stated. For instance, under conditions where both the pressure and the velocity of the moving fluid are substantially constant, I employ the construction especially illustrated in Fig. 1, where 10 indicates the casing of a pump or motor standing upon a foot or base 11. Within the chamber of said casing 10 is located a cylinder barrel 12, said barrel seating at its end against the annular seat plate 13 of the casing, and through which plate the ports lead to the cylinders 36 of the said barrel. The said cylinder barrel 12 is bored centrally and longitudinally, said bore being of larger diameter for the portion of the barrel 18 of a pin 19 extends through said borings, the pin having an'enlarged head .20 in the enlarged portion 14 of the boring of the cylinder barrel. The said head 20 is enlarged abruptly from the shank 18 of the pin 19 so as to form a shoulder 21 opposite the said shoulder 17 on the cylinder barrel, and a roller or ball bearing 22 of any suitable and ordinary construction is arranged between said annular shoulders 17 and 21. The outer end of the shank 18, beyond the casing 10, is threaded to receive a nut 23, andobviously by tightening said nut the cylinder barrel can be drawn firmly to its end seat provided by the plate 13. In practice, the barrel is not drawn against the said plate 13, but is left at a distance of about five thousandths ofan inch therefrom, so that it does not turn in frictional contact therewith,- but upon an interposed film of escaping fluid. Since this construction is used only when the velocity is constantly high, however, it will be understood that the proportion of leakageis so small as to be negligible. This construction permits an unlimited fluid pressure. The said head 20 of the pin 19 is at its end opposite the shank 18 centrally and longitudinally bored to receive the stem 24 which has a balland socket connection as at 25 to the disk-like head 32 of the shaft 33 to which the rods 34 of the pistons 35 in the cylinders 36 of the barrel 12 are connected, all said parts which are not shown in full lines in Fig. 1 being the same as in Fig. 2 where they are clearly shown in detail. Said stem 24 also carries the gear 26 by which the cylinder barrel 12 is caused to rotate with the driving or driven shaft by gear teeth 37 on the disk or head 32 thereof, said gear 26 being fast to the stem 24, as by a key 27, and also keyed to the cylinder barrel as at 28, where its sleevelike end 29 enters the portion 14 of the central boring of the cylinder barrel. Where the'end of the stem 24 enters the boring 30 of the head 20 of the pin 19, it has a long bearing therein which is suitably provided with a bronze bushing 31.

When the pressure of the fluid does not vary materially, but its velocity varies, it is preferable to seat the cylinder barrel by spring pressure, and such a construction is particularly illustrated in Fig. 2 of the drawmgs. Here 110 indicates the casing of the pump or motor, having a foot, 111 on which 11: stands, and 112 is the cylinder barrel arranged 1n said casing with cylinders 40 in 'wlnch reciprocate the pistons 41 which are 60. at its end and through which open the ports connected by rods 42 to the head '43 of the driving (or driven) 'shaft44. 113 is the seat plate against which the cylinder barrel bears tothe cylinders 40, it being remembered that said ports are not less in cross sectional area than the cylinders. The saidcylinder barml 112 is centrally and longitudinally chambered, as at 45, and into this chamber projects axially a pin 119 from the casing 110. lVithin the thickness of the said casing the pin 119 is diametrically reduced to form a shoulder 46 which seats against a corresponding shoulder of the casingthe-reduced extremity 47 of the pin projecting out through the casing wall and receiving a nut pin 119 and provides stop means which I have shown consistingof a collar 51 with a spherical bearing against the bottom of the chamber 45. Between the two stop means just described, one on the pin 119-and the other on the cylinder barrel 112, I arrange a helical spring 52 surrounding the pin 119, and the tension of this spring is such as to hold the cylinder barrel 112 seated against the plate 113. Preferably a ball-thrust bearing 53 and collar 54 are arranged at one end of the spring 52, and washers 55 at the other end. It will be understood, however, that these details could be omitted of varied without departing from the spirit and scope of my invention, and that instead of the somewhat complex stop means which I have described for purposes which will appear hereinafter, other and simpler stop means could be employed as will be. apparent to those skilled in the art.

When the pressure of the fluid varies materially, obviously thespring 52, which has a constant pressure, will not seat the cylinder barrel at the higher fluid pressures so as to prevent leakage, unlessvsaid spring pressure is made so strong as to cause undue friction o-f the cylinder barrel against its seat at the lower fluid pressures, and under such con-.

ditions I reinforce the spring by the pressure of the fluid which is passing through the pump or motor, or might indeed use such pressure without the spring at all. In doing this, the sleeve 49 and collar 51 are packed against thcbarrel chamber 45 and pin 119, respectively, and between said sleeve and collar the pin is bored transversely, as at. 56, to communicate with a central longitudinal passage 57. This passage 57 is, in the solid end portion of the casing 110, intersected by a transverse boring 58 which extends between the inlet and outlet ducts 59, 60, respectively, of the pump or motor for the fluid. (See Fig. 3.) A sliding valve 61 is in said sage 58 and tubular stops 62, into the opposite ends of. the passageto hold her 45 of the cylinder barrel closes around the pas- 63 are screwed said valve 61 against escape and form seats therefor. When the valve 61 is seated on one tubular stop it lies entirely on that side of the passage 57 and permits free passage through the other tubular stop into the pas-- this being that against a surface equal in area to the difference between the cross-sectional area of the chamber 45'where the sleeve 49 engages it and the pin 119 where it passes through the collar 51. By this arrangement, the pressure of the cylinder barrel 1-2 against its seat plate 113 is proportional to the pressure of the fluid, which is of value when such pressure of the fluid varies materially.

In Fig. 2, the stem 124 which connects to vthe head 43 of the driving (or driven) shaft 44; by the ball joint 125, is made fast to the gear 126 by a cross-piece 64:, and extends at its end into a longitudinal socket 130 of the pin 119, a bronze bushing 131 being provided for the bearing. Then said stem is rotatably lockedto the cylinder barrel 11-2 by an annular key 65 upon itself between the barrel and gear 126, which key has longitudinal lugs 66 entering recesses in the end of said gear sleeve and radial lugs 67 entering recesses 68 in the barrel., This connection allows the cylinder barrel a limited motion for adjusting itself, while positively rotatg 1t. i

A relief duct 69 is shown leading from the casing chamber at one side of the cylinder barrelthrough the said casing to a central point of the end or seating face ofsaid bar- The particular adaptability of the diiferent' arrangements. which I have shown to the different conditions under whichthey are to be used, as I have described, will be clearly seen by a brief review of them at this point. The construction of Fig. 1, where the cylinder barrel is held at a fixed clearance from its seat, is simplest and. entirely, adequate,

for example, where the velocityof the liquid in circulation is comparatively high with respect to the pressure and thus the leakage through said clearance spaceis a very small part of the volume of liquidcirculated. If with this construction either the pressure is increased very greatly or thevelocity decreased very greatly, the percentage of leakage will become too'large. i

With the construction shown in Fig. 2,

considered only as tothe spring and disregarding the means for introducing fluid to act in conjunction with said spring, it will be understood that the cylinder barrel is seated with the least possible clearance, the spring effecting such seating and allowing for wear, and thus there is minimum leakage between the cylinder barrel and its seat and the velocity of the liquid in circulation can thereby be low or vary without the proportion of leakage being excessive. Obviously if also the pressure becomes high or excessive, which is the third case or set of conditions considered in the foregoing part of this specification, such pressure would compress the spring and thus unduly increase leakage between the cylinder barrel and its seat, if no means were provided to prevent it, and for this reason I introduce the fluid pressure into the spring chamber,

as described, to assist in holding the cylinder seated under such high or excessive pressures.

Having thus described the invention, what I claim is:

1. The combination with a rotary disk, a rotatable barrel having a plurality of cylinders parallel to its axis, pistons in said cylinders connected to said disk, a support for said barrel providing a seat for the same at its end away from the disk, said support having inlet and outlet ducts and said seat and barrel-end having cooperatingports leading from said ducts to said cylinders, and means for holding said barrel with its axis at an angle to the axis of said disk, of a central pin at the end of said barrel away from its seat pivotally connected to the center of said disk and free to move with the disk independently of the barrel.

2. The combination with a rotary disk, a rotatable barrel with its axis at an angle to the axis of said disk and having a plurality of cylinders parallel to its axis, pistons in said cylinders connected to said disk, and a casing inclosing said barrel and providing a seat for the same at its end away from the disk, said casing having inlet and outlet ducts and said seat and barrel-end having cooperating ports leading from said ducts to said cylinders, of a central pin at the end of said barrel away from its seat and pivotally connected to the center of said disk, at

sleeve on said-pin having one end of itself 7 rotatably fast to the'barrel, and cooperating gears on the other end of said sleeve and the disk respectively.

3. The combination witha shaft, a head on 7 ,ing inlet and outlet ducts and said seat and barrel end having cooperating ports leading from said ducts to said cylinders of asleeve projecting from said bore of the rotary b'arrel rotatably fast with respect thereto, cooperating gears on said sleeve and the shaft head respectively, and a pin inside said sleeve pivotally connected to the center of said shaft hea 4. The combination with a shaft, a head on said shaft, a rotatable barrel with its axis at an angle to said shafthaving a plurality of cylinders parallel to said axis and a central bore, pistons in said cylinders connected to said shaft head, and a casing inclosing said barrel and providing a seat for the same at its end or face away from the shaft, said casing having inlet and outlet ducts and said seat and barrel end having cooperating ports leading from said ducts to-said cylinders, of a stud projecting from said seat axially into said barrel bore, a Sleeve projecting from said bore of the rotary barrel rotatably fast with respect thereto, cooperating gears on said sleeve and the shaft head .respectively, and a pin inside said sleeve pivfitaly connected to the center of said shaft 5. The combination with a shaft, a head on said shaft, a rotatable barrel having a plurality of cylinders parallel to its axis and a central bore, pistons in said cylinders connected to said shaft head, a support for said through, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapts ed to register with said ports in the'seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel,

. of a stud projecting from said seat into said barrel bore and having therein a head opposed to said internal shoulder and adapted to cooperate therewith in holding the barrel to its seat.

8. The combination with a rotary disk,

a rotatable barrel with its axis at an angle to the axis of said disk having a plurality of cylinders parallel to its axis and a cen tral bore providing an interior shoulder,

pistons in said cylinders connected to said.

and barrel end having cooperating ports' leading from said ducts to said cylinders, of a stud projecting. from said seat axially barrel providing a seat for the same at its end away from the shaft, said support having inlet and outlet ducts and said seat and barrel-end having cooperating ports leading from said ducts to said cylinders, and means for holding said barrel with its. axis at an angle to said shaft, of a stud projecting from said seat into said barrel bore and a central -socket, and a pin in saidsocket pivotally connected to the center of the shaft head.

6. The combination with a rotary disk, a

rotatable barrel with its axis at an angle to the; axis of said disk having a plurality of cyllnders parallel to its axis and a central bore, pistons insaid cylindersconnected to said disk, and a casinginclosing said barrel and providing a seat for the same at its end away from the disk, said casing having ina rotatable barrel with its axis at an angle to the axis of said disk having a plurality let and outlet ducts and said seatand barrel end havingcooperating ports leading from said ducts to saidcylinders, of a stud pro-. ecting from sald seat'into said barrel bore and having a central socket, a pin and sleeve 7 one extending into said socket, said pin being pivotally connected to the center of the said disk, and said sleeve having one end of. itself rotatably fast to the barrel, andco ,h

gears on theotheruendof said operating sleeve and the disk respectively.

7. *In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening thereinto-said barrel bore and having a head therein opposed to said internal shoulder and adapted to cooperate-therewith to seat the barrel, -a sleeve projecting from said bore of the rotary barrelrotatably fast with respect thereto, cooperating gears on said sleeve and the disk respectively, and a pin inside said sleeve pivotally connected to the center of said disk.

9. The combination with a rotary disk, a I

rotatable barrel having a plurality of cylinders parallel to its axis and a central bore,

pistons in said'cylinders connected to, said disk, a support for said barrel providing a seat for the same at its end' away from the rotary disk, said support having inlet and outlet ducts and said seat and barrel-end having cooperating ports leading from said ducts to said cylinders, and means for holding said barrel with its axis at an angle to the axis of said disk, of a stud projectingfrom said seat into said barrel bore and having a head adapted to hold the barrel to its seat, said head having a. central socket,

and a pin insaid socket pivotally connected to the center 'ofthe disk. 7

10. The combinationwith a rotary disk,

of cylinders parallel to its axis and a central ore, pistonsin said cylinders connected to said disk, and a casing inclosing said barrel and providing aseat for the same atits end 7 away from the disk, said casing haying inlet and outlet ducts and said seat and barrel end I aving cooperating ports leading from said ducts to said cylinders, of. a stud projecting from said seat into said barrel bore and having ahead adapted to hold the barrel to its seat, said head having'a central socket, a pin and sleeve one extending into said end of said sleeve and the disk respectively.

11. The combination with a shaft, a head on said shaft, a rotatable barrel with its axis at an angle to said shaft having a plurality of cylinders parallel to said axisand a central bore providing an interior shoulder, pistons in said cylinders connected to said shaft head, and a casing inclosing said barrel and providing a seat for the same at its end or face away from the shaft, said casing having inlet and outlet ducts and said seat' and barrel end having cooperating ports leading from said ducts to said cylinders, of a stud projecting from said seat into said barrel bore and having a head therein opposed to said internal shoulder and-adapted to cooperate therewith in holding the barrel to its seat, said head having a central socket, a pin in said socket pivotally connected to the center of the shaft head, a sleeve on said pin having one end of itself keyed in said bore of the barrel, and cooperating gears on the other end of said sleeve and the shaft head respectively.

12. The combination with a rotary disk, a rotatable barrel having a plurality of cylinders parallel to its axis, pistons in said cylinders connected to said disk, a support for said barrel providing a seat for the same at its end away from the disk, said support having inlet and outlet ducts and said seat and barrel-end having cooperating ports leading from said ducts to said cylinders, and means for holding said barrel with its axis at an angle'to the axis of said disk, of a central pin at the end of said barrel away from its seat pivotally connected to the center of said disk and free to move longitudinally with the disk independent of the barrel and. its support.

13. In a rotarypiston unit, the combination with a support-providing a seat with inlet and exhaust ports opening therethrough, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel,

of a stud projecting from said seat and having a head in said bore of the barrel, and a helical spring in said bore between said stud head and interior shoulder.

14:. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therefrom, a barrel adapted at one end to engage said seat and having an annular series. of longitudinal cylinders, with ports adapted to register with said ports in the seat, sa id barrel having in its end away from sald seat an angular recess, of an annular key loose in said recess for turning the barrel, and means for turning said key.

15. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therefrom, a barrel adapted at one end to engage said seat and having an annular series of longi-- tudinal cylinders, with ports adapted to register with said ports in the seat, said barrel having in its end away from said seat an angular recess, of an annular key loose in said recess for turning the barrel, a sleeve rotatably fast with respect to said key, and means for turning said sleeve.

16. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therethrough, a barrel adapted at one end. to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel, of a' stud projecting from said seat into said bore of the barrel, stop means on said stud at a distance from said shoulder of thebarrel, a sleeve on said stud next said stop means having a spherical bearing tion with a support providing a seat with inlet and exhaust ports. opening therethrough, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel, of a stud projecting from said seat into said bore ofthe barrel, stop means on said stud at a distance from said shoulder of the barrel, a sleeve on said stud next said stop means, a collar on the stud next said shoulder of the barrel, and means for. resiliently forcing said collar and sleeve apart.

18. In a rotary piston unit, the combination with a support-providing a seat with inlet and exhaust. ports opening therethrough, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder adjacent to the Seat end of the barrel, of a stud projecting from said seat into said bore of the barrel, stop means on said tud at a distance from said shoulder, and means for introducing the pressure fluid into the barrel bore between said shoulder and stop means.

19. In a rotary piston unit, the combinaiio tion with a support providing a seat with inlet and exhaust ports opening therethrough, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel, of a. stud projecting from said seat axially into 10 said bore of the barrel, opposite sleeves on ister with said portsin the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel, of a stud projecting from said seat into said bore of the barrel, stop means on said stud at a distance from said shoulder of the barrel, a. sleeve on said stud next said stop means, a collar on the stud next said shoulder of the barrel, and means for introducing the pressure fluid between said collar and sleeve.

21. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therethrough, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a. cen-' tral bore providing an' interior shoulder adjacent to the Seat end of the barrel, of a stud 40 projecting from said seat into said bore of the barrel, stop means on said stud at a distance from said shoulder of the barrel, a sleeve on said stud next said stop means having a bearing thereagainst and slidably tight against the wall of the barrel bore, a collar on the stud engaging said shoulder of the barrel and slidably tight against the stud, and means for introducing the pressur fluid between said collar and sleeve.v

22. In a rotary piston unit, the combination with a support providing a seat with in let and exhaust ports opening therethrough,

- a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder' .adjacent to the seat end of the barrel, of a ,stud projecting from said seat into said bore of the barrel, step means on said stud atadistance from sai shoulder, and means for introducing the pressure fluid into the barrel bore between said shoulder and stop means through said stud.

23. In a; rotary piston unit, the combination with a support providing inlet and outlet ducts and a seat with inlet andexhaust ports opening therethrough from said ducts, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to-register with said ports in the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel, of a stud projecting from said seat into said bore of the barrel, stop means on said stud at a distance from said shoulder, said stud having a longitudinal passage opening laterally into the barrel bore between said stop means and shoulder, and the studand support beso ing bored transversely of the stud between the said inlet and outlet ducts of the support, stops in said boring on opposite sides of the stud, and a sliding valve between said stops. i 35 A l. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therethrough, a barrel adaptedat one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat, of means for mechanically exerting a resilient. pressure to .hold said barrel to 1ts seat, and means for supplementing said pressure by pressure from the fluid passing through the rotary unit.

25. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therethrough, a barrel adapted at one end to engage said seat and'having an annular series of longitudinal cylinders with ports adapted to'reglsterwith said ports in the seat and a central bore providing an interior shoulder 1 5 adjacent to the seat end of the barrel, of a stud projecting from said seat into said bore of the barrel, stop means on said stud at a distance from said shoulder, a spring between said shoulder and stop means, and means for introducing the pressure-fluid into the barrel bore between said shoulder and stop means.

26. In a rotary piston unit, the combination with a support providing a seat with 1 inlet and exhaust ports opening therea through, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adapted to register with said ports in the seat and a central bore providing an interior shoulder adjacent to the seat end of the barrel, of a stud projecting from said seat into said bore of the barrel, stop means on said stud at a.

distance from said shoulder of the barrel, a

sleeve on said stud next said stop means, a collar on the stud next said-shoulder of the barrel, a spring between said collar and sleeve, and means for introducing the pressure. fiuidbetween said collar and sleeve.

27. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therethrough, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders with ports adaptedto register with said ports in the seat and a central bore providing an interior shoulderadjacent to the seat endof the barrel, of a stud projecting from said seat into said bore of the barrel, stop means on said stud at a distance from said shoulder of the barrel, a sleeve on said stud next said stopmeans having a spherical bearing thereagainst, a collar on the stud having a spherical bearing against the said shoulder of the barrel, a spring between said collar and sleeve, and means for introducing the pressure fluid between said collar and sleeve.

28 The combination with a shaft, a rotatable member with its axis at an angle to said shaft and having a plurality of cylinders parallel to said axis, pistons in said cylinders connected to said shaft, and a casing inclosing said rotatable member and providing a seat for the same at its end or face away from the shaft, said casing having inlet and outlet ducts and said seat and face having cooperating ports leading from said ducts to said cylinders, said ports of not less" cross-section than their respective cylinders, of a pin pro ecting from the casing'axially into the rotatable member, opposite sleeves on said pin within said rotatable member one slidably tight against the'inember and the other against the pin, and means for introducing the pressure fluid between said sleeves.

29. The combination with a shaft, a rotatable member with its axis at an angle to said shaft and having a plurality of cylinders parallel to said axis, pistons in said cylinders connected to said shaft, and a casing inclosing the said rotatable member and providing a seat for the same at its end or face away from the shaft, said casing having inlet and outlet ducts and said seat and face having cooperating ports leading from sald ducts to said cylinders, saidports of not less cross-section than their respective cylinders, of a pin projecting. from the casing axially intothe rotatable member, opposite sleeves on said pin within said rotatable member one slidably tight against the member and the other against the pin, and means for conducting pressure fluid from said nlet and outlet ducts to the space between said sleeves.

30. The combination with a shaft, a rotatable member with its axis at an angle to said shaft and having a plurality of cylinders parallel to said axis, pistons in said let and outlet ducts and said seat and face spherical bearing against each other, said sleeve slidably fitting the rotatable member,

a stop at the seat end of the rotatable memher, a collar having a spherical bearing against said stop on the rotatable member and slidably fitting the pin, and means for introducing the pressure fluid between said collar and sleeve.

31. The combination with a shaft, a rotatable member with its axis at an angle to said shaft and having a plurality of cylinders parallel to said axis, pistons in said cyl'- inders connected to said shaft, and a casing inclosing said rotatable member and providinga seat for the same at its end or face away fromthe shaft, said casing having inlet and'outlet ducts and said seat and face having cooperating ports leading from said ducts to said cylinders, said ports of not less cross-section than their respective cylinders, of a pin projecting from the casing axially into the rotatable member and having a longitudinal passage opening through its side within said rotatable member, sleeves on said pin within the rotatable member on opposite sides of said passage opening, one sleeve slidably fitting the rotatable member and the other the pin, the casing being bored between its said inlet and outlet ducts transversely of the pin and its said passage, tubular stops in the ends of said boring,'and a sliding valve between said stops.

32; The combination with a shaft, a rotatable member with its axis at an angle to said shaft and having a plurality of cylinders parallel to said axis, pistons in said cylinders connected to said shaft, and a casing inclosing saidrotatable member and providing a seatfor the same at its end or face away from the shaft, said casing having inlet and outlet ducts and said seat and face having cooperating ports leading from said ducts to said cylinders, said ports of not less cross-section than their respective cylinders, of a pin projecting from the casing axially into the rotatable member, opposite sleeves on said pin within said.rotatable member one slidably tight against the member and the other against the pin, means for introducing the pressure fluid between said sleeves, and a helical spring on said pin between said'sleeves. I

'33. The combination with a shaft, a rotatable member with its axis at an angle to said shaft and having a plurality of cylinders parallel to said axis, pistons in said cylinders connected to said shaft, and a casing inclosing said rotatable member and provid- ,ing a seat for the same" at its end or face away from theshaft, said casing having inlet and outlet ducts and said seat having co.- 1

operating ports leading from said ducts, to said cylinders, said ports'of notless cross section than their respective cylinders, of a pin projecting from the casing axially into the rotatable member, a stop at the end of.

said pin away from the seat end of the rotatable member, a sleeve on the pin next said stop comprising, two portions having a spherical bearing against each other, said sleeve slidably fitting the rotatable member,

a stop at the seat end of the rotatable member, a collar having a spherical bearing against said stop on the rotatable member and slidably fitting the pin, means for intr0-' ders parallel to said axis, pistons in said cylinders connected to said shaft, and a casing let and outlet ducts and said seat and face having cooperating ports leading from said inclosing said rotatable member and providing a seat for the same atits end or face away from then-shaft, sa1d casing having inducts to said cylinders, said ports of not less cross-section than their respective cylinders, of means for mechanically exerting a resili-;

ent pressure to hold the face of said rota-' table member against its said seat, and means for supplementing said pressure by the hydraulic pressure of the fluid passing through the cylinders. j

35. In a rotary piston unit, the combination with a support providing a seat with inlet and exhaust ports opening therefrom, a barrel adapted at one end to engage said seat and having an annular series of longitudinal cylinders, with ports adapted to register with said ports in the seat, said barrel having in itsend away from said seat an angular recess with radial extensions, an annular key .loose .insaid recess and having lugs projecting into said radial extensions, and means for turning said key.

36. In a rotary piston unit, the combination with avsupport providing a seat with inlet and exhaust ports opening therefrom, a barrel adapted at one end to engage said seat and'having an annular series of longi-' tudinal cylinders, with ports adapted to register with said ports in the seat, said barrel having inits end away from said seat an angular recess with radial extensions, an an- -nular key loose 1n sa1d recess and having lugs projecting into said radial extensions, a sleeve rotatably fast with respect to said key,

"and means for turning said sleeve.

CHARLES R. PRATT.

In the-presence of- .RUssE'LL M. E ERETT, FRANCES E. BLODGETT. 

